Method of carving duplicate designs



mAug. 11, 1942. v H. R. HELGESON METHOD OF CARVING DUPLICATE DESIGNSFiled Ju'ly 5, 1941 3 'sheets-Sheet 1 FIG. 14.

HAROLD R ."HELGESON A118511, 1942. H. R. HELGr-:soN

METHOD OF CARVING DUPTTIICATE DESIGNS Filed July 5, 1941 s sheets-sheet2 HAROLD R. HELGESON` Aug 1l, 1942 H. R. HELGx-:soN 2,292,996

METHOD OF CARVING` DUPLICATE DESIGNS Filed July 5, 1941 5 Sheets-Sheet 3gwuQ/wbfyc HAROLD R. HELGESON Patented Aug. 11, 1942 UNITED STATES?ATENT =OFFICE METHOD OF vCARVING DUPLICATE DESIGNS 9 Harold R.Helgeson, St. Paul, Minn.

Application July 5, 1941, Serial No. 401,198

7 Claims.

'My invention relatesto a methodof Stenciling, wherein it is desired toprovide a simple process by means of which a stencil having disconnectedportions may be used a number of times.

Stencils used in Sandblasting processes are ordinarily formed of rubberor glue `or some `resilient material, land `are formed by cuttingthrough this rubber or `glue to uncover certain parts of the surface tobe sandblasted. Ihis stencil covers `the work being sandblasted `and theportions uncovered by the stencil are struck by the blast of Sand andthis sand engraves into the body a likeness of the uncovered portion,the

portion of the surface covered by the `stencil standing out in relief.If 'it is `desired to repeat the design, it has been necessary to`prepare a new stencil each time the work is sandblasted.

It is `the object of the present invention to provde a stencil which maybe constructed in such a Way that disconnected iparts of .the stencilwill be held in desired relationship during the application thereof to asurface to be sandblasted and in which the disconnected elements of thestencil are temporarily connected while moving the stencil from onesurface whichhas been sandblasted to another surface which is to be.sandblasted. Thus by `.my `method a `single stencil may be used a greatnumber of times without danger of one part of the `stencil beingimproperly positioned in the design. This method obviates the necessityof cutting a new design for each surface sandblasted `and Ialso.obviates the necessity of assembling the various parts of `the stencilupon the surface to be sandblasted.

It is a feature of my invention that I may cut any stencil whatsoeverwith the parts thereof connected or disconnected, and by the use of my`method I may transfer all of the parts in unison onto the surface to besandblasted or from one such surface to another. This I accomplish by4providing a fracturable lm upon the surface of the stencil which isdestroyed by the force of the sandblast but which may hold the variousparts of the stencil in desired relationship during the applyingprocess.

It is a feature of myrinvention that by the use of my process I mayadhere a new surface of paper, linen or other suitable material to theexposed surface of the stencil in the exact position which thedisassociated parts cf the stencil assume during the Sandblastingoperation, using this film as a vehicle for moving all of the parts toanother surface. Thus the same stencil may be used time after timewithout the various parts thereof gettingV outof alignment or out'ofproper 55 relationship one with respect to another, and the Sandblastingoperation may `be repeated in an extremely short space of time.

It is a feature of my invention to provide a method of Sandblastingwhichinpreferred form utilizes the relative strength of two adhesivesurfaces for its operation. The stencil 'is -adhered to the surface tobe sandblasted with an adhesive of relatively lower strength than theadhesive used for adhering the paper, linen or other film to the exposedsurface of the stencil. Thus When the Sandblasting operation has beencompleted, the film used for the transferring process is adhered to theouter or exposed surface of the iilm with an adhesive stronger than theadhesive holding the stencil to the Sandblasted surface Aso that thestencil will remain on `the flexible film rather than upon the cutlsurface and lwill be removed from the cut surface by the lm.

It is an-added feature of my Vinvention to'provide a method of preparinga stencil for sandblast which may utilize Ya Zinc etching or otherengraving in the preparation of the stencil. In this process a mold,such as a zinc etching,-elec `trotype, or the like, may be filled withrubber paste solution or the like, which is partially set, and rolledsmooth. This rubber or the like is then removed on its exposed surfaceuntil only that portion of the rubber which is receded be-4 low thesurface of the etching or mold remains. By adhering a sheet of paper,linen or the like, to the rubber .receded in the mold or etching, all ofthe parts of rubber originally recessed into the mold are adhered to thelm or sheet which may then be secured to a surface to be sandblasted.Obviously, the reverse of the raisedportions of the mold or casting formthe stencil, and when the Sandblasting takes place the same surface isexposed as would be formed if the mold or etching were printed upon thesurface.

It is a feature of my invention `that through the use of a zinc etching,electrotype or the like, a mold may be made which may be cast into acasing of plaster before the removal of the rear surface thereof in'order to prevent Vinjury tothe etching or electrotype. The rear surfaceof Athe rubber casting may be rubbed away through the use of rubbersolvent or the like, until merely those portions ofthe casting whichoriginally extended doWn below the surface Aof the mold or etchingremain. These portions of the casting may then be connected by a filmadhered thereto so that all of the parts of rubber will be supportedupon the 4film in proper relationship and so that these parts may beeasily assembled upon a surface to be sandblasted.

A further feature of my invention resides in the fact that my inventionmay be accomplished by covering a mold with a plastic mass such asrubber,ernbedding a screen or the like into the rubber ush with thesurface of the design thereon, removing the plastic mass and the screenfrom the mold, and stripping the rubber from the surface of the screenon the side thereof opposite the stencil design. This leaves a stencilhaving a reinforcing screen adhered to one surface thereof, which screenmay be placed either in contact with, or spaced from, the work surfacewhile Sandblasting. This method obviates the necessity of rubbing excessrubber from the mold surface in the manner previously `ascribed.

It is a further feature of my invention that a screen adhered to onesurface of the mold may be replaced when Worn through, providing a rigidstencil which may be renewed. Where adhering of the stencil to the worksurface is impractical, difhcult, or costly, the stencil may be securedto material such as screen during the carving process. This screen maybecome injured during the process, but supports the elements of thestencil properly throughout. If the screen is damaged, it is replaced byapplying a cloth or paper sheet to the exposed stencil surface, removingthe stencil from the screen, and applying the stencil to a secondscreen, just as it is moved from one work surface to another.

It is a feature of my invention that through the use of this castingprocess, sandblast patterns may be formed at a low cost and in a shortperiod of time which would require countless hours to reproduce if itwere necessary to cut these patterns from a sheet of rubber or glue. Alarge drawing of the pattern may be made and this drawing may be reducedphotographically and made into a zinc etching, which in turn may beusedY as the mold for forming the stencil. Thus by my method I provide asimple method of forming intricate stencils having disconnected partswhich would be virtually impossible to construct through the use of theusual methods of procedure.

These and other objects and novel features of my invention will be moreclearly and fully set forth in the following specification and claims.

In the drawings forming a part of my specification:

Figure 1 is a perspective view of a pattern after the same has been cut.

Figure 2 illustrates diagrammatically a sheet of linen, paper, or thelike, being applied to the surface of the design.

Figure 3 diagrammatically illustrates the design being removed from thesurface upon which it was formed, showing the various parts of thedesign adhered to the backing sheet.

Figure 4 illustrates the actual Sandblasting operation with the designshown in position upon the surface to be sandblasted.

Figure 5 illustrates the application of a new film or backing sheetapplied to the surface of the stencil.

Figure 6 illustrates the various parts of the stencil being removed fromthe sandblasted surface, together with the film or backing'sheet.

Figure 7 illustrates in section the formation of the stencil before theSandblasting operation.

Figure 8 illustrates in section the appearance -of the stencil after thestart of the Sandblasting operation after the backing film has beenentirely destroyed.

Figure 9 is a perspective View of a rubber paste solution applied to thesurface of a zinc etching or electrotype.

Figure 10 illustrates the removal of the rubber from the etching orelectrotype after the same has set.

Figure 11 illustrates in section the rubber applied either to theetching or electrotype or upon a cast base.

Figure 12 is a cross-sectional View of the stencil after the rubber hasbeen removed down to the surface of the etching or mold block.

Figure 13 is a cross-sectional view through the mold block shown inFigures 1l and 12, showing a film applied to the surface of the stencil.

Figure 14 is a View similar to Figure 13, showingl the removal of thestencil from the mold block or etching.

Figure 15 illustrates the Sandblasting operation in which the backingsheet or exible film is destroyed.

Figure 16 illustrates the application of a new film sheet to the surfaceof the stencil.

Figure 17 illustrates the removal of the stencil from the sandblastedsurface assembled in readiness for use upon a new surface to besandblasted,

Figure 18 illustrates in perspective a stencil sheet having a film sheetsecured to a surface thereof.

Figure 19 is an enlarged section through a portion of the stencil ofFigure 18.

Figure 20 is a perspective view of the stencil of Figures 18 and 19,showing a'screen adhered thereto.

Figure 21 is an enlarged sectional view of the stencil shown in Figure20.

Figure 22 is a sectional view of the stencil of Figure 21 in use.

Figure 23 illustrates in perspective a mold used for casting a stencildevice.

Figure 24 is a sectional view through the mold of Figure 23, showingsand blast resistant material, such as rubber paste, applied thereto.

Figure 25 is a view similar to Figure 24 showing a screen embedded inthe rubber paste, and extending flush with the mold surfaces. To holdthe screen taut, a frame is illustrated.

Figure 26 illustrates the stencil, screen and screen frame removed fromthe mold.

Figure 2'7 is a sectional detail, showing the manner in which the rubberor other material is stripped from one surface of the screen.

Figure 28 shows the stencil of Figure 2'7 in use upon work beingsandblasted.

In order to accomplish my method I first place upon a table or anysuitable support, such as l0, a, sheet of rubber or other suitablecomposition designed to stand up under a Sandblasting process. Thissheet of material Il may be adhered to the surface of the table orsupport I0 during the cutting of the stencil. Figure 1 shows a gure cutfrom the stencil and including a relative'- ly large opening ifi havinga series of individual stencil elements I3 within this opening which aredisconnected with each other and with the Vremainder of the stencil. Itwill be understood that under most circumstances this type of stencilwould have to be cut directly upon the work which is to be sandblast, orelse'the stencil would have to be assembled with all of the parts I3 inproper relationship within the 4opening I2.

In order to accomplishmy methodV I then place conditions.

encaisse over `the surface of the stencil sheet I I, a film `of adhesivelland to theiadhesive fadherela exible `film Aof linen, paper, or `thelike, .indicated :by the Ynumeral I5. Theadhesive 14 which is used toadhere vthe film I to the stencil II, provides a stronger .bond .thanthe adhesive holding the stencil sheet I I to thesupport I0, so that theelements ofthe stencil will adhere tothe film I5 and .will be removedtherewith. In ,Figure 3 of the .drawings I disclose the stencil beingremoved from the support I0. It will be noted that the backing sheet I5supports `the elements I3 of the stencil II in proper relationship .andall of the elements of the stencil remain in the same relative .positionas Iin the Figure 1, while these elements were being cut.

The foregoing method of preparing the stencil on the backing `sheet ,mayvary under certain If `it .is desired, the linen or paper sheet I5 maybe adhered to the rubber before the stencil is cut and the stencil.prepared by cutting through the rubber but not through the `paper orlinen. However the vstencil `is prepared, whether it be machine-cut ormanually cut, is somewhat immaterial as long as all of the parts f3 of'the stencil whichare disconnected from the remaining parts of thestencil, are assembled in proper relationship .and adhered to a sheetsuch .stencil and striking the surface of the body I6 being sandblasted.The design is then cut into .the surface of .the body `I6 not .coveredby the stencil II. The force of the .sand blast removes the .greaterpart, if not all, of the 4linen film as such material is not capableofstanding up under the strain of the `sand blast while .the rubber orother -material forming `.the sheet II is designed towithstand thisaction.

After zthe Sandblasting operation takes place the next step iin theprocess is .to remove all of .the parts .of .the stencil from thesandblasted .surface in their proper spaced relationship. This Iaccomplish by the use -of a new sheet `I5 of linen, paper, vor othersuitable .material coated with adhesive as illustrated a-t I9. ThcsheetI5 iscoated :with adhesive as isalso the exposed surface .of the stencilII if it is so desired, .and the sheet I5 is pressed rmly in place overthe surface of the stencil. The adhesive I9 is preferably -a strongerbond with the .material forming the stencil .than .is the adhesiveholding `the parts of the stencil to the surface of the body I6. The.entire stencil .may be removed as indicated in `Figure .6 .of .thedrawings, .the backing sheet I5 forming a support .for the remainingportion of the stencil sheet II .and `including the separateV .parts I3of thestencil which-do not contact .any other portion .of the stencil.This same procedure may .be followed .any desired number of times withinthe limits of ,strength of the Ystencil. .It .will be noted .that eachtime the stencil his applied, the various elements forming the com-;plete stencil are placed .in .definite relationship on the surface tobegsandblasted; and each time these ipartsareremoved, they remain in.the exact relationship in which'they lare applied. For this vreason Ihave rfound that by my method, the same stencil having many disconnectedparts may be used over and over again lwithout in anyway affecting thestencil except to wear the same slightly as is usual under constantSandblasting.

My method is also applicable for use in conjunction with zinc etchings,electrotypes or other relief molds. In Figure 9 of ,the drawings, Idisclose a zinc etching AZIJ mounted upon a wooden block 121| and-show`placed over the surface of the etching a `rubber paste solution 22.This paste .solution fills the low portions of the Zinc etching and asillustrated in the cross-sectional view in Figure 1l, also covers the.high places of the etching with a thin film. rLrhe low places of theetching .are indicated in the figure at 23, while the surface portionsof the etching are shown at 24. This method is ordinarily followed as itis diflicult to merely ll the low portions .23 .of the mold or etchingup to the level of the raised surfaces or printing surface-smi ofthesame.

After the rubber paste has partially set, a strip of water-moistened.linen or the like may be placed over the surface of the rubber and therubber rolled out smooth with a suitable rolling device. The linen isthen removed. This step is employed merely to flatten the upper surfaceof the rubber and need not be employed if some other means is used tomaintain the upper surface of the .rubber normally relatively fiat.After the solution has properly set one of two methods of procedure maybe followed. rlhe rst and most simple of these procedures is to rubYdown the surface 25 of the rubber casting with a cloth-covered block,using rubber solvent as a medium. The rubber solvent gradually wearsaway the upper surface of the vrubber until this surface is flush withthe printing surface of the etching or mold. In other words, the lowportions 23 cf the zinc etching are filled with rubber up to theprinting surfaces, but no rubber projects above the printing surfaces ilof the mold.

When the rubber casting has been rubbed down to the printing surface, asindicated in Figure 12 of the drawings, the surface of the rubbercasting is `coated with an adhesive or cement 25 and a backing sheetl2l' is applied thereto. In this case, as in other instances in mymethod, itis usually most practical to coat the surface to be covered`as well as -the flexible sheet, with the adhesive, let these adhesivecoated surfaces set, and then apply the two coated surfaces together.The stencil may then be removed from the etching Tic in the mannerillustrated in Figure le of the drawings, the various `separate parts ofthe stencil being held in place upon the linen or paper backing sheetThe stencil may then be secured to a ybody 29 to be sandb-lasted bycoating the surface 3B of the stencil with adhesive and applying thestencilento the surface to be sandwiched. During the Sandblastingoperation, the sand is forced through the nozzle I'I at a high rate ofspeed, and this laction cuts through the linen or paper backing orcovering sheet 2l. During the Sandblasting process the sheet 2l isdestroyed, but the parts are secured in definite relation on the body 29to be sandblasted, and thus .they remain .in fixed relationship.

At the completion of the .Sandblasting operation, anew backing sheet 2lof linen or paper .or the like is applied over the vexposed surface ofthe .stencil being secured thereto by adhesive 3|,

.flexible Sheet 34 is adhered thereto.

This adhesive 3l is a stronger adhesive then that holding the stencil tothe body 29 so that the Stencil may be removed as indicated in Figure 17of the drawings, the design sandblasted then showing up clearly upon thebody 29.

The second procedure which may be followed after the rubber pastesolution has been formed on the zinc etching or electrotype 20 issomewhat similar to the method just described. In this form of myinvention, the rubber mass is permitted to set while in the positionillustrated in Figure 9. This rubber is then removed, inverted andplaced upon a wax surface or the like. The design which has been. formedin the rubber by the zinc etching or electrotype is then uppermost. Aplaster casing is then cast over the rubber mold and permitted toharden. When complete, this plaster casing will have the sameconformation -as the etching or electrotype from which the rubber moldwas made.

The surface of the rubber is then rubbed away by means of acloth-covered block moistened with a rubber solvent. This block andcloth acts as a buffer to rub away the surface of the rubber down to thesurface of the plaster casting. I

then find a construction virtually identical to that illustrated inFigure 12, the lower portion being in this case a plaster castingbearing portion of rubber which may or may not be connected. The

upper surface of the casting and rubber is then coated with adhesive anda linen or paper backing sheet is applied to this Surface. The backingsheet is rolled into intimate Contact with all of the rubber particlesin the mold. The stencil thus formed may be removed from the plastercast, or if necessary the plaster cast may be broken and cracked away,leaving the rubber particles adhered to the surface of the backingsheet. The stencil may be then used by coating the surface 33 thereof inthe manner which has been previously explained.

It will be found in some instances that the depth of the recesses insome of the zinc etchings or electrotypes is so uneven that it isdiiiicult to place the stencil on a flat surface by placing adhesive onthe surface 3i] of the mold. In instances where it is desired toduplicate an electrotype or Zinc etching of this type, it is oftenpreferable to coatl the linen or paper covering 2 with adhesive andsecure this surface of the stencil to the body 29 to be sandblasted.Thus a clear, sharp impression is assured. With this arrangement, it isdifficult to assemble the Various elements of the stencil in theirproper relationship with another backing sheet such as 2'! after theSandblasting operation has taken place, but a new stencil may readily beformed from the electrotype or zinc etching. This procedure has theadvantage that intricate designs may be drawn on a large scale andreduced on the Zinc etching, and in Such work it is usually worth whileto form a new stencil for each Sandblasting operation. It will beunderstood, however, that this method utilizes my method of assemblingall of the disconnected parts of the stencil onto a backing sheet sothat the parts may be assembled in proper relationship upon the surfaceto be sandblasted.

In Figure 18 of the drawings, I disclose a stencil 33 which is adheredto a flexible sheet 34, by the adhesive 3E. This stencil is either cutwhile mounted upon a working surface and has the flexible sheet 34adhered thereto, or if it is desired, the stencil sheet 33 may be cutwhile the A coating of adhesive 36 is then applied to the oppositesurface of the stencil sheet 33 from'that bearing the flexible sheet 34,and a screen sheet 31 is likewise coated with adhesive. The screen isapplied to the adhesive coated surface of the stencil sheet 33 and thisscreen is thus afxed to the stencil. In this way a rigid stencil isformed which may be merely clamped against the work during theSandblasting process. During the Sandblasting process the screen 31 maybe on the underside of the stencil sheet 33, adjacent the work surface39, or may be on the surface of the stencil sheet 33 which is spacedfrom the work surface. During the Sandblasting operation the sand isblown through the screen 3l, this screen permitting sufrlcient of thesand to be forced therethrough to cause proper carving of the worksurface. If the screen 31 is positioned adjacent the work surface 39 inthe manner illustrated in Figure 22 of the drawings, this screen maysomewhat deflect the path of the sand, providing an appearance along theedges of the apertures 40 formed in the work surface 33 by the sandwhich simulates a hand tooled job. If the screen 31 is on the outersurface of the stencil sheet 33, the path of the sand is not as closelydened by the screen, and a smoother carving operation is permitted.

After the work has been carved by the sandblasting process, it may befound that the screen 3l is intact or portions of the screen may havebecome injured during the carving process. If

the screen is in good shape at the end of the carving operation, thestencil may be moved to another work surface and another Similar designcarved. If, however, the Screen has been injured by the blast of Sandduring the Sandblasting operation, a new sheet of flexible material suchas linen, paper or the like may be adhered to the surface of the stencilsheet 33 opposite that bearing the screen 31, and the stencil sheet maybe removed from the screen and a new screen may be applied thereto. Inother words in this type of construction the stencil may be moved fromone screen to another in the same manner that was previously describedfor moving the stencil from one work surface to another.

In Figure 23 of the drawings I disclose another form of constructionwhich discloses a different method of forming stencils. In this method,a mold is first prepared as illustrated in Figure 23. This mold 4| maybear indicia such as 42 and may be provided with an edge rim 43. Themold 4| may be in the form of an electrotype, zinc etching, or the like,or may be a stencil cut in any suitable firm material. It is desirable,however, that the mold be formed with the indicia and rim extending to acommon plane as is usual in the case of zinc etchings, electrotypes, andthe ike.

The mold 4| is then covered with a coating of rubber paste 44 or thelike which lls the interstices between the various parts of the indicia52 and between the indicia 42 and the rim 43. This rubber paste i4 ispreferably applied in liquid or molten state so as to form a plasticmass covering the mold 4i. While the rubber paste 44 or the like isstill in a plastic State or in molten form, a screen 43 is forced downupon the mold so that the screen lies iiush upon the rim 43' and theindicia 42. It is extremely desirable that the screen 45 contact thesurface of the indicia or design 42. As illustrated in Figure 25 of thedrawings and in order to maintain the screen taut during this insertion,the screen may be clamped or otherwise secured within a screen frame 46.

When. the. screen has been forced down into the plastic mass 44',.itAwould. appear in section in the mannerv illustrated in Figure 25' of thedrawings.

When the' rubber paste or other material 44 has had an opportunity toVset or to assume desired'shapetheA frame 46 with its screen 45 may belifted from the mold 4 I; this screen and sten.- cil sheet appearing asindicated in the perspective viewof. Figure 26 ofthe drawings. When theplastic or flexible stencilsheet has dried or set suiiiciently, theportion of the rubber paste or other material which has been forcedthrough the screen as the screen is pressed down over the stencil may bepeeled off from the screen in the manner illustrated in Figure 2'7 ofthe drawings. It Will be found that the plastic stencil sheet having thescreen 45 embedded therein will peel off from the screen under pressureso that the screen is adhered to one surface of the remainder of thestencil rather than embedded within the stencil as in Figures 25 and 26.The portion of rubber paste or the like s1 which is peeled away from thescreen is discarded or remelted or dissolved, the remaining stencilhaving openingstherethrough up to the screen and the screen permittingthe sand to pass therethrough during the Sandblasting operation, orremove screen.

In Figure 28 of the drawings I disclose a work surface 49 having astencil sheet 44 adhered thereto or clamped against the surface thereof,this stencil sheet 44 having openings 50 therein so that during theSandblasting operation the sand will be blown through the screen andthrough the openings in the stencil sheet 44 to carve the work surface49.

In adhering two laminations of stencil material together or in securinga flexible sheet or screen to a sandblast resistant material, it iscommon practice to coat both the contacting surfaces with a cement whichwill cause the uniting of the two surfaces when placed in contact. Thuswhere adhesive is used in any of the positions described, this adhesiveis commonly of a type similar to rubber cement in the use of which bothcontacting surfaces are coated. In case other adhesives are used,however, it may be necessary to coat only one of the contactingsurfaces.

I have found my method extremely satisfactory and have found that agreat number of patterns may be sandblasted from the same stencil in ashort period of time even though the parts of the stencil are relativelydisconnected. I have also found that I have been able to sandblastreplicas of intricate designs formed on a large scale and reduced bymolding rubber or the like over these zinc etchings or electrotypes. Ihave found it possible to form minute lettering by this process and tosandblast designs which would be almost impossible to cut manually.

In a color printing process, it is customary to use a series of dierentcolor cuts, each of which prints a design in one color, which designsmay be superimposed one upon the other to produce a final result. In asimilar manner it is possible for me to provide a series of stencilseach of which is of a different shape or bears an individual design, butall of which register to produce a single finished design.

In accordance with the patent statutes, I have described the principlesof operation of my method; and while I have endeavored to set forth thebest embodiments thereof, I desire to have it understood that these areonly illustrative of Ways of carrying out my invention and that obviouschanges may be made within the scope of the` following claims withoutdeparting from the spirit of my invention.

I claim:

1. The method of forming duplicate designs through the use of asandblast resistant stencil, and a series of flexible fracturablesheets, the method consisting in cutting the stencil, mounting thesamein desired relationship on a fracturable sheet,V adhering the stencil tothe surface uponfwhich' the design is to be sandblasted, sandblastingthe design on the surface, the force of the sand fracturing the saidsheet, applying a new fracturable sheet to the stencil in place of theone destroyed by the Sandblasting process, and removing the stencil fromthe sandblasted surface for use on another surface to be sandblasted.

2. The method of preparing sandblasted designs with a stencil formed ofmaterial resistant to the Sandblasting process and mounted upon a sheetwhich may be destroyed by the Sandblasting process, the methodconsisting in applying the stencil to the surface, Sandblasting throughthe stencil to produce the design and to destroy the sheet vupon whichthe stencil was mounted, applying a new mounting sheet similar to thatdestroyed to the stencil, and removing the stencil from the sandblastedsurface with said sheet.

3. A method of Sandblasting designs with the use of a blast resistantstencil and a film nonresistant to a sand blast, the method consistingin applying the stencil to the work to be sandblasted, Sandblasting thesurface exposed through the stencil, adhering the non-resistant lm tothe stencil, removing the stencil from the work sandblasted togetherwith the film, applying the stencil and film to another surface to besandblasted, and Sandblasting the film, and stencil, the non-resistantfilm being destroyed by the blast to expose the stencil and permittingthe blast to strike the work surface through the stencil.

4. A method of Sandblasting designs with the use of a blast resistantstencil having openings therethrough and a non-resistant film, themethod consisting in applying the stencil to the work surface to besandblasted, adhering the nonresistant film to said stencil, the nlmoverlying the openings in the stencil, removing the stencil from thework surface together with the film, applying the stencil and film to asecond work surface to be sandblasted, and sandblastingrthe film andstencil, the blast destroying the portion of the film overlying theopenings and striking the second work surface exposed thereby throughsaid stencil.

5. A method 'of Sandblasting designs with the use of a blast resistantstencil anda non-blast resistant film, the stencil comprising a seriesof disconnected parts, the method consisting in applying the stencil toa work surface to be sandblasted, directing a sandblast against theportion of the work surface exposed by the stencil, adhering thenon-blast resistant film to the stencil, the nlm adhering to all of thedisconnected parts of the stencil to connect the same, and removing thefilm with the stencil adhered thereto from the work surface.

6. A method of sandblasting duplicate designs with a stencil comprisinga plurality of disconnected parts and a non-blast resistant film, themethod consisting in applying the stencil to a work surface to besandblasted, Sandblasting the Work surface through the stencil, adheringthe non-blast resistant film to the disconnected parts of the stencil,removing the film With the stencil adhered thereto from the Worksurface, applying the stencil and lm to a second Work surface, andSandblasting the second Work surface through the stencil, the exposedlrn being destroyed by the sandblast.

7. A method of Sandblasting similar designs on a plurality of Worksurfaces with the use of a stencil and a, nonblast resistant lrn, themethod consisting in adhering the stencil to a Work surface with anadhesive means, Sandblasting the work surface through the stencil,adhering the lm to the stencil with an adhesive stronger than thatadhering the stencil to the Work surface, removing the lm and stencilfrom the Work surface, adhering the stencil to a second work surface,and Sandblasting the stencil and lm, the exposed lm being destroyed toexpose the second work surface not covered by the stencil, and sand-HAROLD R. HELGESON.

